As cables laying in each country in the world is seeking to be disposed underground as much as possible, and this chiefly relies on the network of pipelines. The cable splice boxes that connect cables underground are situated in the manholes and hand-holes of underground cable pipelines, and many manholes and hand-holes accumulate huge amounts of water yearly, thus the cable splice boxes situated within these holes are immersed in water yearlong. Please refer to FIG. 1, which is the cross-section diagram of the underground layout of cable splice boxes. In FIG. 1, manhole covers 11, 12 have manholes 111, 121 situated underneath. Cable splice boxes 13, 14 are disposed in manholes 111, 121, and cable splice boxes 13, 14 are connected by cable 16. Cable splice boxes 13, 14 are connected by cables 15, 17, respectively, to other cable splice boxes (not shown). In practice, cables 15, 16, 17 in manholes 111, 121 are curled up. Regardless of whether a cable splice box is made with an electric cable or a fiber optic cable, if there is insufficient waterproofing, water leaking into cable splice boxes due to water built up from manholes or hand-holes will affect the transmission quality of the cable in addition to accelerating the deterioration of the cable, resulting in transmission malfunctions and reduction of the lifespan of cables.
Existing technology of cable networking and cable splicing techniques, in telecommunications, cable television, monitoring systems and other types of cable transmission industries, has long relied on heat-shrink cable splice boxes. Although the manufacturing cost for a heat-shrink cable splice box is comparatively lower, the cable has a longer applicable external diameter, along with simpler and faster construction, thus being widely used in the industry, the heat-shrink cable splice box is heavily criticized for its common water leakage problems. Please refer to FIG. 2(A), which is a vertical view of a heat-shrink cable box in the current technology. In FIG. 2(A), hollow cylindrical pipes 23A, 23B, 23C, 23D, 23E, 27 are configured on cable entrance board 21 of heat-shrink cable splice box 20 (abbreviated as splice box), and main cables 24A, 24B go through hollow cylindrical pipe 27 into splice box 20. The main cables 24A, 24B are separated by manifold clip 29 used for heat-shrink tubes. Divided cables 25A, 25B, 25C, 25D, 25E, respectively, go through hollow cylindrical pipes 23A-23E to enter splice box 20. Please refer to FIGS. 2(B) and 2(C), which are diagrams showing the waterproofing structure of heat-shrink cable splice box in the current technology. In FIGS. 2(B) and 2(C), heat-shrink cable splice box 30 (abbreviated as splice box) at least is constructed with protective cover 22, cable entrance board 31 and hollow cylindrical pipes 32, 33A, 33B. The user firstly takes main cables 24A, 24B to penetrate hollow cylindrical pipe 32 that is wrapped by heat-shrink tube 36, through opening 38A into the splice box. Main cables 24A, 24B are spaced by a manifold clip used for heat-shrink pipes, then heat-shrink tube 36 and manifold clip are torched with fire, and the waterproofing of the cable entry board whereby main cables 24A, 24B goes through is accomplished. The divided cable 35B penetrates hollow cylindrical pipe 33B that is wrapped by heat-shrink tube 37, through opening 38B into the splice box, and then heat-shrink pipe 33B is torched, in order to complete the waterproofing of the entry board where the divided cable 35B enters and exits. The main cables 24A, 24B and divided cable 35B have their spliced part stored in the cable splicing distribution board 39. However, when torching the heat-shrink pipe 37, the already torched heat-shrink pipe 36 being nearby heat-shrink pipe 37 is subjected to further heating, thus softens, loosens and causes water leakage in splice box 30. Similarly, during the torching of other heat-shrink pipes of cable entry opening 33A, neighboring heat-shrink pipes that are already torched are subjected to further heating, therefore they soften, loosen and cause water leakage in splice box 30.
For example, a communication optical cable splice box's cable entrance board is usually 15 cm to 20 cm in diameter or even smaller, while the cable entry board usually is required to a provide access for 6 or more cables penetrated, so that the openings for cable access on the cable entry board are very close to each other. Therefore, in the current waterproofing technology of cable access openings of the heat-shrink cable splice box, one has to complete torching the heat-shrink tube of the first cable access opening, and then torch heat-shrink tubes for other cable access openings. This often results in heat-shrink tubes that are already completed to be subjected to further torching, causing them to soften, loosen and resulting in water leakage problems in splice boxes. This shortcoming and vital flaw has always been the most pressing and difficult problem that needs to be solved, in the technological field.
Taiwan's telecommunications industry, for example, due to the popularity and trend of fiber-optic broadband service, Chunghwa Telecom in recent years layed out fiber-optic cables on a massive scale and heavily utilized fiber-optic cable splice boxes for accessing fiber-optic cables, and also announced that beginning in 2009, for five consecutive years, will invest NT $30 billion a year, a total of NT $150 billion of funds for fiber-optic network infrastructure. In recent years, the company placed heat-shrink cable splice boxes in manholes and hand-holes, with far more than half of them suffering from serious leakage. As the water leakage problem in heat-shrink cable splice box is not resolved, the company has had to purchase mechanical cable splice boxes that are 3 times more expensive than heat-shrink cable splice boxes, and a variety of mechanical means of sealing to establish a waterproof structure for cable access openings. The suitable cable outer diameter for these waterproof cable access openings is restrictively small, accessories needed are diverse and complicated, with cumbersome construction procedures, needing a variety of tools, resulting in inconvenience and higher costs of construction, among other issues. Mechanical cable splice boxes, in addition to being less straightforward and efficient than heat-shrink cable splice boxes, the procurement costs have increased threefold. Thus, by eliminating the shortcomings and improving the waterproofing capacity of heat-shrink cable splice boxes, not only can communication quality issues due to water leakage in heat-shrink cable splice boxes be avoided, it also can significantly reduce the cost of investing enterprises.
It is therefore attempted by the applicant to deal with the above situation encountered in the prior art.